GREEN RANKING FOR 2009
Ranking: 13
Worth: £6.8bn
Green investment: Solar power

Twins Andreas and Thomas Strungmann are Germany’s top entrepreneurs. Their father, Ernst, ran the family-owned drug company, Durachemie, until 1979, when he asked his sons to take it over. The brothers sold Durachemie in 1986 and used the proceeds to launch a hugely successful pharmaceutical company called Hexal. In 2005 the Strungmanns sold the business as well as their 68% stake of US Eon Labs to the Swiss company Novartis for $7.5 billion. Since then they have been investing their wealth in biotechnology, property and, more recently, solar power: in February last year they took a stake in Conergy, the German solar-power specialist.The Strungmanns have a £6.8 billion fortune.